Re: 8 bit vs 16 bit workflow
Re: 8 bit vs 16 bit workflow
- Subject: Re: 8 bit vs 16 bit workflow
- From: "Martin [apple account]" <email@hidden>
- Date: Fri, 03 Aug 2001 13:24:49 +0100
on 3/8/01 10:44 am, neil snape at email@hidden wrote:
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are. High bit output devices don't exist so unlikely to see an improvement
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on the output side. Image output devices are not foreseen to be in high bit
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either for obvious technical reasons. Therefore yes 16bit files have little
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or no visual difference on output.
Not really that bothered about output type -- we can run tests to inkjet,
Pictro, 300 line screen film and Cromalin or even back out to tranny if
necessary. But why bother -- you can see little difference on screen, or
with the eyedropper
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This is where pure math vs. what you see will bring this discussion up
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front. Since all transforms pass through numeric lut's there will be
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rounding errors. One could say insignificant but look closely and you'll
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easily see that 16 bit keeps many more levels in check (when converting back
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to 8 bit for output) than heavy edits in 8bit.
That's my point -- the rounding errors are insignificant because the human
eye cannot detect them. It doesn't matter how many transforms you do, layer
after layer of the craziest curves yields such similar results in 8 bit or
16 that I am dubious that it is worth the trouble at all.
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Yes
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there is an obvious advantage to 16 bit especially negative scans or digital
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input, as you said when there is heavy editing to do.
I said that this was my original belief: "if only I'd done that in 16 bit
then it wouldn't look quantized" etc. But when I have the time to test the
theory the results are so close that I judge them insignificantly different.
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> The majority of our images are scanned between 75 and 200 megs (RGB). If we
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> seriously look at doubling this data and losing 85 per cent of Photoshop's
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> capabilities there had better be some good reasons to do so!
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The larger images have more detail spread out over the area to maintain so
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in any case there will still be enough data to print. The dithering or
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interpretation by the rip making a median of the pixel values will no doubt
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smooth out differences anyway.
My point is: if you can't determine significant difference between 8 and 16
bit images by any useful criteria (eye for example) then why bother
overloading your system with double the data and removing nearly all the
useful retouching features of your favourite image editing programme?
--
Martin
Idea Digital Imaging Ltd - the "image" specialists
http://www.idea-digital.com